Name

glPushMatrix, glPopMatrix — push and pop the current matrix stack

C Specification

void glPushMatrix(

void);

void glPopMatrix(

void);

Description

There is a stack of matrices for each of the matrix modes. In
GL_MODELVIEW
mode, the stack depth is at least 16. In the other modes,
GL_PROJECTION, and
GL_TEXTURE,
the depth is at least 2. The current matrix in any mode is
the matrix on the top of the stack for that mode.

glPushMatrix
pushes the current matrix stack down by one, duplicating the
current matrix. That is, after a glPushMatrix
call, the matrix on top of the stack is identical to the one
below it.

glPopMatrix
pops the current matrix stack, replacing the current matrix
with the one below it on the stack.

Initially, each of the stacks contains one matrix, an
identity matrix.

It is an error to push a full matrix stack, or to pop a
matrix stack that contains only a single matrix. In either
case, the error flag is set and no other change is made to GL
state.

Notes

Each texture unit has its own texture matrix stack. Use
glActiveTexture
to select the desired texture matrix stack.

Errors

GL_STACK_OVERFLOW is generated if
glPushMatrix
is called while the current matrix stack is full.

GL_STACK_UNDERFLOW is generated if
glPopMatrix
is called while the current matrix stack contains only a single
matrix.